Fix 500 error on compare page
Fix 500 error on compare page

Signed-off-by: Dmitriy Zaporozhets <be23d75b156792e5acab51b196a2deb155d35d6a@gmail.com>

dplarson/gitlabhq,mr-dxdy/gitlabhq,iiet/iiet-git,screenpages/gitlabhq,sue445/gitlabhq,ferdinandrosario/gitlabhq,ikappas/gitlabhq,martijnvermaat/gitlabhq,openwide-java/gitlabhq,Soullivaneuh/gitlabhq,MauriceMohlek/gitlabhq,yatish27/gitlabhq,openwide-java/gitlabhq,dplarson/gitlabhq,MauriceMohlek/gitlabhq,dreampet/gitlab,jrjang/gitlab-ce,shinexiao/gitlabhq,SVArago/gitlabhq,cui-liqiang/gitlab-ce,sonalkr132/gitlabhq,fpgentil/gitlabhq,szechyjs/gitlabhq,stoplightio/gitlabhq,shinexiao/gitlabhq,LUMC/gitlabhq,Telekom-PD/gitlabhq,stoplightio/gitlabhq,htve/GitlabForChinese,axilleas/gitlabhq,ksoichiro/gitlabhq,icedwater/gitlabhq,icedwater/gitlabhq,szechyjs/gitlabhq,martijnvermaat/gitlabhq,dwrensha/gitlabhq,ferdinandrosario/gitlabhq,duduribeiro/gitlabhq,ksoichiro/gitlabhq,allysonbarros/gitlabhq,mrb/gitlabhq,MauriceMohlek/gitlabhq,axilleas/gitlabhq,SVArago/gitlabhq,yatish27/gitlabhq,darkrasid/gitlabhq,screenpages/gitlabhq,iiet/iiet-git,jrjang/gitlabhq,cui-liqiang/gitlab-ce,sonalkr132/gitlabhq,icedwater/gitlabhq,jirutka/gitlabhq,koreamic/gitlabhq,stoplightio/gitlabhq,htve/GitlabForChinese,mr-dxdy/gitlabhq,dplarson/gitlabhq,ferdinandrosario/gitlabhq,louahola/gitlabhq,daiyu/gitlab-zh,dwrensha/gitlabhq,jrjang/gitlabhq,screenpages/gitlabhq,fpgentil/gitlabhq,daiyu/gitlab-zh,t-zuehlsdorff/gitlabhq,SVArago/gitlabhq,mrb/gitlabhq,louahola/gitlabhq,yatish27/gitlabhq,mrb/gitlabhq,ttasanen/gitlabhq,Datacom/gitlabhq,mr-dxdy/gitlabhq,dwrensha/gitlabhq,jrjang/gitlab-ce,duduribeiro/gitlabhq,gopeter/gitlabhq,ikappas/gitlabhq,sue445/gitlabhq,t-zuehlsdorff/gitlabhq,daiyu/gitlab-zh,Datacom/gitlabhq,duduribeiro/gitlabhq,mmkassem/gitlabhq,jrjang/gitlabhq,ikappas/gitlabhq,ikappas/gitlabhq,shinexiao/gitlabhq,ksoichiro/gitlabhq,Soullivaneuh/gitlabhq,LUMC/gitlabhq,mmkassem/gitlabhq,ttasanen/gitlabhq,fpgentil/gitlabhq,dplarson/gitlabhq,mrb/gitlabhq,openwide-java/gitlabhq,cui-liqiang/gitlab-ce,gopeter/gitlabhq,LUMC/gitlabhq,mmkassem/gitlabhq,iiet/iiet-git,axilleas/gitlabhq,htve/GitlabForChinese,dreampet/gitlab,htve/GitlabForChinese,allysonbarros/gitlabhq,louahola/gitlabhq,larryli/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,sonalkr132/gitlabhq,darkrasid/gitlabhq,larryli/gitlabhq,koreamic/gitlabhq,mmkassem/gitlabhq,larryli/gitlabhq,icedwater/gitlabhq,jrjang/gitlab-ce,daiyu/gitlab-zh,allysonbarros/gitlabhq,martijnvermaat/gitlabhq,jrjang/gitlab-ce,Datacom/gitlabhq,ttasanen/gitlabhq,mr-dxdy/gitlabhq,koreamic/gitlabhq,axilleas/gitlabhq,shinexiao/gitlabhq,sue445/gitlabhq,Telekom-PD/gitlabhq,koreamic/gitlabhq,screenpages/gitlabhq,allysonbarros/gitlabhq,jirutka/gitlabhq,jirutka/gitlabhq,Soullivaneuh/gitlabhq,LUMC/gitlabhq,openwide-java/gitlabhq,sue445/gitlabhq,fpgentil/gitlabhq,t-zuehlsdorff/gitlabhq,SVArago/gitlabhq,sonalkr132/gitlabhq,yatish27/gitlabhq,MauriceMohlek/gitlabhq,szechyjs/gitlabhq,iiet/iiet-git,darkrasid/gitlabhq,cui-liqiang/gitlab-ce,gopeter/gitlabhq,martijnvermaat/gitlabhq,louahola/gitlabhq,darkrasid/gitlabhq,larryli/gitlabhq,ttasanen/gitlabhq,Telekom-PD/gitlabhq,stoplightio/gitlabhq,Telekom-PD/gitlabhq,dwrensha/gitlabhq,ferdinandrosario/gitlabhq,ksoichiro/gitlabhq,duduribeiro/gitlabhq,szechyjs/gitlabhq,dreampet/gitlab,jirutka/gitlabhq,jrjang/gitlabhq,gopeter/gitlabhq,Datacom/gitlabhq,Soullivaneuh/gitlabhq